1. Field of the Invention
The present invention relates to a structure for connecting branch pipes in a high-pressure fuel manifold generally employed in diesel engines of various kinds of vehicle or the like. More particularly, the present invention pertains to an improvement in the structure for connecting branch pipes in a high-pressure fluid manifold which is disposed near such a diesel engine so as to serve as a passage for supplying the engine with fuel under an ultra-high pressure, i.e., 1000 kg/cm.sup.2 or more.
2. Description of the Related Art
FIG. 4 shows one example of the conventional connecting structure of the type described above. As illustrated, a plurality of through-holes 13 are provided in the peripheral wall of a main pipe 11 for supplying high-pressure fuel in such a manner that the through-holes 13 are spaced apart from each other in the longitudinal direction of the main pipe 11 and are communicated with a flow passage 12 defined inside the main pipe 11, and a branch pipe 14 is fitted into each through-hole 13 and brazed or welded to the main pipe 11 as shown by the reference symbol W, thus connecting the branch pipe 14 to the main pipe 11.
The above-described prior art suffers, however, from the problem that leakage of fuel through the weld W or coming off of the branch pipe 14 often occurs as the weld strength deteriorates due to the above-described fitting engagement between the branch pipe 14 and the main pipe 11 and incomplete welding despite the fact that there are demands for sufficiently high weld strength at the joint to endure the repetitive supply of fuel under ultra-high fluid pressure, i.e., 1000 kg/cm.sup.2 or more, during use, as a result of the improvement in the engine mechanism, and also vibrations applied from the engine.